New Aleph Mini PCB GB

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jleaman

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#1
New Aleph Mini

Just posting the new layout from briangt I have been bugging him to start something up and instead he has done up a new board. Im looking for comments. Im going to start a group buy after i get a parts list and comments.. So any one interested or like the new layout ?
 

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#2
The new layout is based off of my old SMD layout for the Mini-A (see Grey's thread for schematic). I got the boards made back in 2003:
An externally hosted image should be here but it was not working when we last tested it.

more pics of old board:
http://www.briangt.com/gallery/mini-a

The layout is almost same as the previous one, except that I changed everything over to through-hole.

I will not be selling these boards, and am just offering the new board for a group buy, as Jason has been bothering me about this ever since I finished the SMD layout.

The new layout is smaller, 2" x 2.5". I also made a version that is a little bigger and has 4 devices (same schematic as the Aleph 3).

--
Brian
 
#5
Brian,

Sorry to be a pain but is it possible to add a second through hole for terminal blocks for +V and -V? From the looks of it you just need to add another through hole for a 2 position terminal block for each rail. If it is not possible, it is no great shakes. It just makes it easier to remove the board if you want to do a tweak or repair something. Sure beats soldering and resoldering the wires from the board.
 
#6
kilowattski said:
Brian,

Sorry to be a pain but is it possible to add a second through hole for terminal blocks for +V and -V? From the looks of it you just need to add another through hole for a 2 position terminal block for each rail. If it is not possible, it is no great shakes. It just makes it easier to remove the board if you want to do a tweak or repair something. Sure beats soldering and resoldering the wires from the board.
Click to expand...

This is possible.

Other ideas I had for the board:
- increase the number of output resistors and add extra pad to allow board to be used as a front end board only. (as with my original Aleph boards)
- add NPN compensation cap to Q5 as done in the Aleph30 (0.001uf from C -> B)
- create pcb set with power supply board also, accepting 4 x 22,000uf caps (35mm snap-in, as used on new chipamp power supply board).
- add resistor and placement for an LED on the board (or wired off board)

I think that increasing the board size to 2.9" x 2" (2.9" = width of the power supply layout I can modify: http://www.briangt.com/gallery/snubber ) would allow for all of these features in a small mini-A implementation.

The 220uF caps on the board allow for up to 35v caps to be used. I could also increase the diameter to allow for up to 50v if desired, but I think that 35v should suffice, still allowing for rails to make a 60w amp if output devices are wired in parallel external to the pcb.

Any comments?

--
Brian
 
#8
jleaman said:
Since i'm the one that bugged you to get it going lets make to revisions then one with 2 fets and another with 4 fet's ...


I like the Led idea too. : O ) me personally i like to solder the power wires to the board using that wire i was talking about last-night ...


Ill post a pic of the wire..
Click to expand...

I think that it is best to keep the board with 2 output devices, and then make a different board later on if the need is there for 2 output devices. My concern with 5 output devices per side is that the board needs to be made bigger to get the devices spaced farther apart on the heatsink.
 
#10
Brian,

I was putzing around with photoshop. Below is a modified picture of the board with the two extra pads for the terminal blocks. It is up to you how you implement them. I think 220 microfarad 35 V Cerafines would work real well. I also like the idea of the power supply as well.
 

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#11
Brian may i start another thread on that 15 -+ psu you gave me pictures for as dave and i both agree we could bennifit from it and many others on the forum..

Also lets get a regulated or a psu board for these mini a's simular to the ones you just made for the gain clones with fred's a power led connectors for input and out put maybe a small fuse per rail..


Jason
 
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